1. Field of the Invention
The invention relates to an emergency release locking system for a lid closing a trunk of a vehicle, particularly a motor vehicle. Further, the invention also relates to a vehicle with a locking system of this type and to a method for operating the locking system.
2. Description of the Background Art
To prevent an unauthorized opening of lids or doors of vehicles, particularly motor vehicles, these are typically assigned a locking device, which fixes the lid in its locked position. Such locking devices predominantly have a lid lock which is attached to the body of the vehicle and comprises a rotary latch and a pawl working together therewith. In the locked state, the rotary latch secures a bow-shaped or hook-shaped closing element, attached to the lid. The rotary latch is typically acted upon by a spring force in the direction of its release position. In order to keep the rotary latch in its locked position, it locks in place with the pawl, which holds the rotary latch in the locked position against said spring force. By actuation of the pawl and the subsequent release of the latching, the rotary latch is released and the lid can be opened. In the case of lids of vehicles, which are located in the front of the vehicle and open forwards, an additional safety mechanism is needed, which prevents the lid from being opened completely during driving due to the air flow after improper actuation or improper closing of the lid. This is particularly the case with engine hoods and in vehicles where the trunk is located in the front of the vehicle. In this respect, to secure the lid a pivotable catch hook is provided, which in its catch position catches the closing element, released by the rotary latch, in a gap opening position of the lid. The catch hook in its catch position thus permits opening of the lid only up to the gap opening position in which the lid is typically pushed by a spring element. Further or complete opening of the lid is only possible when the catch hook is released from the closing element. This can occur either by a pivoting of the closing element or by reactuation of the locking device, as disclosed, for example, in DE 20 2009 010 975 A1, which corresponds to US 20120138492. The locking device disclosed here is actuated to open the lid by a Bowden cable.
Locking devices of this type increasingly must reliably fulfill more exacting requirements in regard to safety aspects and regulations. Legislative measures, for example, the regulations for the vehicle market that came into effect in the United States of America on Sep. 1, 2001, for internal trunk operation in motor vehicles, “Internal Trunk Release FMVSS 401,” require a trunk emergency release system with which a person locked in the trunk can free himself by operating a suitable handle of an emergency release system. According to the definition underlying this regulation, a trunk is a space intended for the transport of luggage or cargo, which is separated from the driver compartment or passenger compartment of the vehicle by a partition or by a fixed or fold-down row of seats, can be closed outwardly by a trunk lid or deck lid, and has an interior space which with a closed and locked trunk lid can accommodate a 3-year-old child dummy. In vehicles in which, due to the design, for example, because the engine is placed in the rear of the vehicle, the trunk is located in the front, therefore under a front lid, the following provisions should be considered according to the aforementioned regulations:
When the vehicle is moving forward at a speed of 5 km/h or greater, in the event of improper or unintentional unlatching of the lid lock by a secondary securing device, for example, by the above-described catch hook, the trunk lid must be prevented from opening further, on the one hand, in order to protect the person possibly present in the trunk and, on the other, to prevent the swinging open of the lid due to the air flow, which would impede the view of the vehicle driver in the direction of travel in a most disadvantageous manner.
When the vehicle is moving forward at a speed less than 5 km/h, the trunk lid must be released by actuation of the emergency release system via a suitable handle. In addition, it is allowable at this speed that the emergency release system has a releasing effect on the catch device to enable the wider opening of the trunk lid. When the vehicle is standing still, an unimpeded opening of the trunk lid must be assured upon actuation of the emergency release system.
Very different designs for closing systems with such an emergency release function have been known for quite some time. DE 10 2006 012 062 A1, which corresponds to U.S. Pat. No. 8,215,683, which is incorporated herein by reference, and which discloses a closing device, in particular for a trunk lid of a motor vehicle with a rotary latch which interacts with a lid-side locking clamp. The rotary latch is held securely in a closed position by means of a pawl. The closing device comprises a lid-side catch hook which can be caused to engage with a catch element after movement of the pawl to the open position and by which the lid is to be kept in the holding position, whereby the catch hook can be moved from the holding position to an open position in which the lid can be completely opened. The rotary latch and the catch hook are made as separate parts. The pawl of the rotary latch and the catch hook can thereby be actuated sequentially one after the other via a common remote actuation element, whereby to actuate the catch hook a catch hook lever is provided, which acts on the catch hook disposed on the lid side. In order the meet the safety provisions here in regard to the speed-dependent allowability of an emergency release, in the trunk, particularly in the front trunk, a handle for emergency release is provided, which is assigned a blocking device with which the actuation of the catch hook can be stopped depending on the driving speed. The blocking device includes an electromagnet, which is energized or not depending on the driving speed. In regard to the speed-dependent emergency release addressed above, DE 10 2007 029 679 A1 discloses a comparable solution, whereby an actuator, not more closely defined, is provided here which is activated depending on the driving speed in order to prevent a lid located in the front area from being opened completely while the vehicle is moving.
Further, a method for releasing a trunk lid of a vehicle is proposed in DE 101 43 263 C1, which corresponds to U.S. Pat. No. 6,831,376. In this regard, a release handle, which for its part is connected to a control unit in the vehicle, is disposed in the interior of the trunk. When the release handle is actuated, a microswitch is actuated and the contact is detected in the control unit as a signal for the actuation of the release handle. Parallel to the signal of the release handle, the signal of the speed of the vehicle is detected in the control unit. The control unit analyzes, these signals and when suitable conditions are present (e.g., speed is zero) controls an adjusting element, which then causes the release of the catch hook for the trunk lid. If a speed greater than zero is detected, a predetermined delay time is started and information is simultaneously provided to the driver. After the delay time has expired, the trunk lid is released for opening. More precise data on the adjusting element per se cannot be derived from this publication.
The conventional solutions have in common that to meet the higher safety standards or safety provisions, defined more closely above, in regard to the speed-dependent allowability of an emergency release, the blocking device engaging at the catch hook or the actuator is subject to very high numbers of load cycles (>500,000) in that the blocking device blocks the catch hook at a vehicle speed of, for example, ≧5 km/h, in order to a release it again for a possibly complete opening of the trunk lid at a driving speed <5 km/h. The blocking device disclosed in DE 10 2006 012 062 A1 in the form of an electromagnet is certainly suitable for satisfying the high numbers for load cycles in the case of sufficient stability. Irrespective of this, such a blocking device is associated with relatively high costs.
In contrast, DE 10 2005 021 740 A1, which corresponds to U.S. Pat. No. 7,341,289, which is incorporated herein by reference, discloses an emergency release system for a trunk lid with a trunk lock, which comprises at least one lock latch and a cooperating locking part, with a catch which limits the trunk opening motion and comprises a catch hook, which can be actuated from outside the trunk to cancel the motion limitation, and a cooperating catch hook engagement element, and with an emergency release system, which is disposed in the trunk and which when actuated acts to open the trunk lock and to release the catch device. To offer the higher safety standard and to meet safety provisions in regard to the speed-dependent allowability of an emergency release, the actions applied by the emergency release system on the catch lock and the catch are decoupled from one another. Further, a speed-dependent electrical actuating element is provided, which is supplied with current vehicle speed values tapped at a front wheel. If upon actuation of an emergency release system located in the trunk, the currently measured driving speed exceeds a corresponding threshold, the actuating element activates a blocking lever, which for its part acts on the catch hook engagement element such that the catch hook retains its engaged position during opening (release) of the trunk lid and prevents wider opening of the trunk lid. In other words, the actuating element with the blocking lever is advantageously activated only when actuation of the emergency release system is detected. A much lower number of load cycles is to be set, which results in lower wear of the actuating element and thereby a longer lifetime. Irrespective of this, however, a situation is also conceivable in which the catch hook engagement element due to the actuation of the emergency release system is already in an open position and movement of the catch hook to its release position is made possible. If at this moment a vehicle speed greater than a specific threshold value is detected, the trunk lid can be opened despite the increased driving speed or open automatically due to, for example, air flow, which can have a very disadvantageous effect both on the vehicle driver due to obstruction of the forward view and also on the child, for example, in the trunk.